Porous substrate holder with thinned portions

Abstract

A substrate support system comprises a substrate holder for supporting a substrate. The substrate holder comprises a central portion sized and shaped to extend beneath most or all of a substrate supported on the substrate holder. The central portion has one or more recesses defining thinned portions of the central portion. The one or more thinned portions may comprise at least about 10% of an upper or lower surface of the central portion. The central portion is formed of a porous material, such as a material having a porosity between about 10-40%, configured to allow gas flow therethrough.

1 . A substrate support system comprising a substrate holder for supporting a substrate, the substrate holder comprising a central portion such that the substrate is spaced apart from the central portion when the substrate is supported by the substrate holder, the central portion having one or more recesses defining thinned portions of the central portion, the central portion being formed of a material having a porosity between about 10%-40% and configured to allow gas flow therethrough. 
     
     
         2 . The substrate support system of  claim 1 , further comprising a hollow support member having an inlet adapted to engage an outlet of a gas-conveyor to facilitate gas flow from the gas-conveyor into the hollow support member, the hollow support member having one or more upper open ends adapted to support the lower surface of the central portion of the substrate holder, the one or more upper open ends configured to convey gas upwardly through the central portion of the substrate holder. 
     
     
         3 . The substrate support system of  claim 2 , wherein the one or more upper open ends are configured to convey gas upwardly into the recesses and the one or more thinned portions. 
     
     
         4 . The substrate support system of  claim 2 , wherein the central portion further comprises a plurality of passages extending from the upper surface of the central portion to the lower surface of the central portion, and wherein the hollow support member comprises a hollow body and a plurality of hollow arms extending upwardly from the hollow body, the one or more upper open ends of the hollow support member comprising upper ends of the arms, wherein the passages are configured to receive gas from the upper ends of the arms. 
     
     
         5 . The substrate support system of  claim 4 , wherein lower ends of the passages are located within support recesses in the lower surface of the central portion, each of the support recesses configured to closely receive an upper end of one of the arms. 
     
     
         6 . The substrate support system of  claim 1 , wherein the one or more thinned portions comprise at least about  10 % of an upper or lower surface of the central portion of the substrate holder. 
     
     
         7 . The substrate support system of  claim 1 , wherein the porosity of the material forming the central portion is between about 20% to 30%. 
     
     
         8 . The substrate support system of  claim 1 , wherein the substrate holder is formed of a porous composite silicon carbide. 
     
     
         9 . The substrate support system of  claim 1 , wherein the substrate holder comprises a porous material having a density in a range of about 0.5 to 1.5 g/cm 3 . 
     
     
         10 . The substrate support system of  claim 1 , wherein the at least one thinned portion has a thickness in a range of about of about 0.01-0.10 inch. 
     
     
         11 . The substrate support system of  claim 1 , wherein the one or more thinned portions comprise cut-outs. 
     
     
         12 . The substrate support system of  claim 1 , wherein the one or more recesses are formed in an upper surface of the central portion. 
     
     
         13 . The substrate support system of  claim 1 , wherein the one or more recesses are formed in a lower surface of the central portion. 
     
     
         14 . The substrate support system of  claim 1 , wherein the one or more recesses include recesses formed in an upper surface of the central portion and recesses formed in a lower surface of the central portion. 
     
     
         15 . A substrate support system comprising a substrate holder for supporting a substrate, the substrate holder comprising a central portion having an upper surface, a lower surface, and a plurality of recesses, each recess being formed in one of the upper surface and the lower surface, each recess defining a thinned portion of the central portion, the central portion formed of a porous material. 
     
     
         16 . The substrate support system of  claim 15 , further comprising a hollow support member having an inlet adapted to engage an outlet of a gas-conveyor to facilitate gas flow from the gas-conveyor into the hollow support member, the hollow support member having one or more upper open ends adapted to support the lower surface of the central portion of the substrate holder, the one or more upper open ends configured to convey gas upward through the central portion of the substrate holder. 
     
     
         17 . The substrate support system of  claim 16 , wherein the one or more upper open ends of the hollow support member consists of one open end defined by an annular wall with an upper edge configured to stably support the substrate holder. 
     
     
         18 . The substrate support system of  claim 17 , wherein the hollow support member comprises a generally horizontal base member and the annular wall, the annular wall extending upward from the base member. 
     
     
         19 . The substrate support system of  claim 15 , wherein the porous material has a porosity in a range of about 10%-40%. 
     
     
         20 . The substrate support system of  claim 15 , wherein the substrate holder includes at least one spacer extending upwardly from the central portion and having an upper support surface raised above the upper surface of the central portion, the spacer's upper support surface being configured to support the substrate such that a gap region is formed between the upper surface of the central portion and a bottom surface of the substrate. 
     
     
         21 . The substrate support system of  claim 20 , wherein the gap region has a substantially uniform height. 
     
     
         22 . The substrate support system of  claim 15 , wherein the plurality of recesses consists of about 80 to 5000 recesses. 
     
     
         23 . The substrate support system of  claim 15 , wherein the upper or lower surface of the central portion of the substrate holder has a density of recesses of about 0.1 to 7 recesses per cm. 
     
     
         24 . A method of processing a substrate, comprising:
 providing a substrate holder comprising a central portion having one or more recesses defining thinned portions of the central portion, wherein the one or more thinned portions are configured to allow gas flow therethrough;   resting a substrate onto the substrate holder so that a gap region is formed between an upper surface of the central portion and a bottom surface of the substrate; and   directing an inert or cleaning gas through the one or more thinned portions of the substrate holder.   
     
     
         25 . The method of  claim 24 , further comprising directing a generally horizontal flow of a reactive gas above the substrate, wherein the steps of directing the reactive gas and directing the inert or cleaning gas overlap in time. 
     
     
         26 . The method of  claim 24 , wherein directing an inert or cleaning gas through the one or more thinned portions comprises:
 providing one or more hollow arms;   positioning an upper end of each arm directly below one of a plurality of passages extending from the upper surface of the central portion to a lower surface of the central portion; and   directing the gas upwardly into each of the hollow arms, wherein the gas flows from the arms through the passages into the gap region and then flows down through the one or more thinned portions.   
     
     
         27 . The method of  claim 24 , wherein directing an inert or cleaning gas through the one or more thinned portions comprises:
 providing a hollow support member comprising a base member and an annular structure extending upwardly from the base member, the annular structure having an upper edge configured to restrict fluid flow across an interface between the upper edge and a lower surface of the substrate holder;   resting the lower surface of the central portion of the substrate holder on the upper edge of the annular structure of the hollow support member; and   directing the gas upwardly into the hollow support member, wherein the gas flows from the hollow support member upward through the one or more thinned portions of the central portion of the substrate holder.   
     
     
         28 . The method of  claim 24 , further comprising directing a second flow of gas underneath and generally parallel to a lower surface of the central portion of the substrate holder. 
     
     
         29 . The method of  claim 24 , wherein the one or more thinned portions comprise at least about 10% of the upper surface or a lower surface of the central portion of the substrate holder. 
     
     
         30 . A substrate holder for supporting a substrate, the substrate holder comprising a central portion having an upper surface, a lower surface, and a plurality of recesses each formed in one of the upper surface and the lower surface, each recess defining a thinned portion of the central portion, the central portion formed of a porous material configured to permit gas flow therethrough without allowing light to pass therethrough, the central portion including at least one through-hole configured to receive an upward flow of gas.